Sydänglykosidit

Sydänglykosidit is a collective term for a group of naturally occurring chemical compounds found in plants, particularly those belonging to the Apocynaceae and Liliaceae families. These compounds are characterized by a steroid nucleus and a glycosidic linkage, meaning a sugar molecule is attached to the steroid part. This glycosidic structure is crucial to their biological activity.

The primary pharmacological significance of sydänglykosidit lies in their potent effects on the cardiovascular system. They are known to act as cardiac glycosides, influencing the contractility and rate of the heart muscle. Specifically, they inhibit the sodium-potassium ATPase pump in cardiac cells, leading to an increase in intracellular calcium concentration. This increase in calcium enhances the force of myocardial contraction, making them useful in treating certain heart conditions like congestive heart failure and atrial fibrillation.

However, due to their narrow therapeutic index, sydänglykosidit can also be toxic if administered incorrectly or in excessive doses. Symptoms of toxicity can range from gastrointestinal disturbances and visual disturbances to severe cardiac arrhythmias. Historically, these compounds have been extracted from plants like foxglove (Digitalis) and lily of the valley (Convallaria) for medicinal purposes, forming the basis of several well-established cardiac medications. Research continues to explore their therapeutic potential and refine their clinical application.